Your ultimate goal in the game is quite simply to kill more times than you die. If everyone does that, you win. Your enemy knows that too. Some of the enemy are better players than you. You need to figure out what kind of team you're facing. How many are tanks, how many are going to get in your face, and how many are going to be bouncing across the battlefield like armed and explosive chickens.
Head towards the enemy spawn and get to know when you need to ADS on each map. Keep an eye on the minimap and use your ears. Strategy 1 is quite effective against scrubs or new players. Get to the enemy spawn in time for the first wave of deaths, and you're guaranteed a multi kill. Then gtfo for 30 seconds, and repeat for the rest of the game. I've gone 23-3 like this recently. Defending against it is difficult but you need to get them off your spawn. If you play as a tank and your team is getting killed in the spawn, go and help. Just leave a scrub or two.
